If you are unsure of your chassis model please contact technical support during our opening hours and our team will be more than happy to help.
Alternatively you may have success by following the below steps.
1. Open a command prompt window
2. Type "wmic baseboard get product" (without quotes)
3. Your chassis model is then listed.
Another alternative is using CPU-Z and choosing the "Mainboard" tab and checking the "Model" listed. You can download this from the below link.
I hope this is helpful, again please feel free to contact us if you are unsure.